Velocity Field Measurements of the California Sea Lion Propulsive Stroke Using Bubble PIV

California sea lions are among the most agile of swimming mammals. Most marine mammals swim with their hind appendages—flippers or flukes, depending on the species—whereas sea lions use their foreflippers for propulsion and maneuvering. The sea lion’s propulsive stroke generates thrust by forming a jet between the flippers and the body and by dragging a starting vortex along the suction side of the flipper. Prior experiments using robotic flippers have shown these mechanisms to be possible, but no flow measurements around live sea lions previously existed with which to compare. In this study, the flow structures around swimming sea lions were observed using an adaptation of particle imaging velocimetry. To accommodate the animals, it was necessary to use bubbles as seed particles and sunlight for illumination. Three trained adult California sea lions were guided to swim through an approximately planar sheet of bubbles in a total of 173 repetitions. The captured videos were used to calculate bubble velocities, which were processed to isolate and inspect the flow velocities caused by the swimming sea lion. The methodology will be discussed, and measured flow velocities will be presented.

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Epidemiological models to control the spread of information in marine mammals

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2016.2037 ◽

2016 ◽

Vol 283 (1844) ◽

pp. 20162037 ◽

Cited By ~ 6

Author(s):

Zachary A. Schakner ◽

Michael G. Buhnerkempe ◽

Mathew J. Tennis ◽

Robert J. Stansell ◽

Bjorn K. van der Leeuw ◽

...

Keyword(s):

Marine Mammals ◽

Foraging Behaviour ◽

Social Transmission ◽

Sea Lion ◽

California Sea Lions ◽

Sea Lions ◽

Promising Tool ◽

Diffusion Analysis ◽

And Control ◽

The Impact

Socially transmitted wildlife behaviours that create human–wildlife conflict are an emerging problem for conservation efforts, but also provide a unique opportunity to apply principles of infectious disease control to wildlife management. As an example, California sea lions ( Zalophus californianus ) have learned to exploit concentrations of migratory adult salmonids below the fish ladders at Bonneville Dam, impeding endangered salmonid recovery. Proliferation of this foraging behaviour in the sea lion population has resulted in a controversial culling programme of individual sea lions at the dam, but the impact of such culling remains unclear. To evaluate the effectiveness of current and alternative culling strategies, we used network-based diffusion analysis on a long-term dataset to demonstrate that social transmission is implicated in the increase in dam-foraging behaviour and then studied different culling strategies within an epidemiological model of the behavioural transmission data. We show that current levels of lethal control have substantially reduced the rate of social transmission, but failed to effectively reduce overall sea lion recruitment. Earlier implementation of culling could have substantially reduced the extent of behavioural transmission and, ultimately, resulted in fewer animals being culled. Epidemiological analyses offer a promising tool to understand and control socially transmissible behaviours.

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Unlocking the Role of a Genital Herpesvirus, Otarine Herpesvirus 1, in California Sea Lion Cervical Cancer

Animals ◽

10.3390/ani11020491 ◽

2021 ◽

Vol 11 (2) ◽

pp. 491

Author(s):

Alissa C. Deming ◽

James F. X. Wellehan ◽

Kathleen M. Colegrove ◽

Ailsa Hall ◽

Jennifer Luff ◽

...

Keyword(s):

Mrna Expression ◽

Marine Mammals ◽

Sea Lion ◽

California Sea Lions ◽

Primary Tumors ◽

Viral Loads ◽

Sea Lions ◽

Herpesvirus 1 ◽

Urogenital Carcinoma

Urogenital carcinoma in California sea lions (Zalophus californianus) is the most common cancer of marine mammals. Primary tumors occur in the cervix, vagina, penis, or prepuce and aggressively metastasize resulting in death. This cancer has been strongly associated with a sexually transmitted herpesvirus, otarine herpesvirus 1 (OtHV1), but the virus has been detected in genital tracts of sea lions without cancer and a causative link has not been established. To determine if OtHV1 has a role in causing urogenital carcinoma we sequenced the viral genome, quantified viral load from cervical tissue from sea lions with (n = 95) and without (n = 163) urogenital carcinoma, and measured viral mRNA expression using in situ mRNA hybridization (Basescope®) to quantify and identify the location of OtHV1 mRNA expression. Of the 95 sea lions diagnosed with urogenital carcinoma, 100% were qPCR positive for OtHV1, and 36% of the sea lions with a normal cervix were positive for the virus. The non-cancer OtHV1 positive cases had significantly lower viral loads in their cervix compared to the cervices from sea lions with urogenital carcinoma. The OtHV1 genome had several genes similar to the known oncogenes, and RNA in situ hybridization demonstrated high OtHV1 mRNA expression within the carcinoma lesions but not in normal cervical epithelium. The high viral loads, high mRNA expression of OtHV1 in the cervical tumors, and the presence of suspected OtHV1 oncogenes support the hypothesis that OtHV1 plays a significant role in the development of sea lion urogenital carcinoma.

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Common cancer in a wild animal: the California sea lion ( Zalophus californianus ) as an emerging model for carcinogenesis

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2014.0228 ◽

2015 ◽

Vol 370 (1673) ◽

pp. 20140228 ◽

Cited By ~ 24

Author(s):

Helen M. Browning ◽

Frances M. D. Gulland ◽

John A. Hammond ◽

Kathleen M. Colegrove ◽

Ailsa J. Hall

Keyword(s):

Marine Mammals ◽

Wild Animal ◽

Zalophus Californianus ◽

Sea Lion ◽

California Sea Lions ◽

California Sea Lion ◽

Sea Lions ◽

Terrestrial Mammals ◽

The Usa ◽

Urogenital Carcinoma

Naturally occurring cancers in non-laboratory species have great potential in helping to decipher the often complex causes of neoplasia. Wild animal models could add substantially to our understanding of carcinogenesis, particularly of genetic and environmental interactions, but they are currently underutilized. Studying neoplasia in wild animals is difficult and especially challenging in marine mammals owing to their inaccessibility, lack of exposure history, and ethical, logistical and legal limits on experimentation. Despite this, California sea lions ( Zalophus californianus ) offer an opportunity to investigate risk factors for neoplasia development that have implications for terrestrial mammals and humans who share much of their environment and diet. A relatively accessible California sea lion population on the west coast of the USA has a high prevalence of urogenital carcinoma and is regularly sampled during veterinary care in wildlife rehabilitation centres. Collaborative studies have revealed that genotype, persistent organic pollutants and a herpesvirus are all associated with this cancer. This paper reviews research to date on the epidemiology and pathogenesis of urogenital carcinoma in this species, and presents the California sea lion as an important and currently underexploited wild animal model of carcinogenesis.

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Quantifying errors associated with using fecal samples to determine the diet of the California sea lion (Zalophus californianus)

Canadian Journal of Zoology ◽

10.1139/z01-078 ◽

2001 ◽

Vol 79 (6) ◽

pp. 1080-1087 ◽

Cited By ~ 12

Author(s):

Anthony J Orr ◽

James T Harvey

Keyword(s):

Zalophus Californianus ◽

Correction Factors ◽

Sea Lion ◽

California Sea Lions ◽

California Sea Lion ◽

Fecal Samples ◽

Sea Lions ◽

Mesh Bag ◽

Estimate Number ◽

Fish Otoliths

The purpose of this study was to quantify the errors associated with using fecal samples to determine the diet of the California sea lion (Zalophus californianus). Fishes and squids of known size and number were fed to five sea lions held in enclosures with seawater-filled pools. Enclosures were washed and pools were drained periodically so that sea lion feces could be collected using a 0.5 mm mesh bag. Fish otoliths and squid beaks were collected from feces and used to estimate number and size of prey eaten. An average of 50.7% (SE = 6.4%) of 430 fishes and 73.5% (SE = 12.0%) of 49 cephalopods fed to sea lions were represented by otoliths and beaks in feces, respectively. Estimated lengths of fish from feces were less than lengths of fish fed to sea lions by an average of 30.1% (SE = 2.8%). Beaks were not digested significantly; estimated lengths of squid were underestimated by an average of only 3.3% (SE = 1.5%) relative to actual lengths. Passage rates of otoliths varied, but more than 70% were recovered within 48 h after the fish was consumed. Passage rates of beaks were generally less than those of otoliths; six beaks (11%) were collected in feces 4 days after the squid were eaten. Correction factors were created to more reliably estimate the number and size of fishes and cephalopods eaten by California sea lions.

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The Protection of Animals During Warfare

AJIL Unbound ◽

10.1017/aju.2017.69 ◽

2017 ◽

Vol 111 ◽

pp. 272-276

Author(s):

Jérôme de Hemptinne

Keyword(s):

Marine Mammals ◽

Bottlenose Dolphins ◽

Rapid Rate ◽

Human Beings ◽

Armed Groups ◽

Military Operations ◽

Protected Species ◽

California Sea Lions ◽

Animal Products ◽

Sea Lions

In times of war, the first instinct is to relieve the suffering of human beings. Environmental and animal interests are always pushed into the background. However, warfare strongly affects natural resources, including animals, which makes animal issues a matter of great concern. Certain species have been vanishing at a rapid rate because of wars, often with disastrous effects on the food chain and on the ecological balance. Indeed, belligerents rarely take into account the adverse consequences of their military operations on animals. They even take advantage of the chaotic circumstances of war in order to poach protected species and to engage in the trafficking of expensive animal products. While generating billions of dollars each year, such poaching and trafficking allows armed groups to grow and to reinforce their authority over disputed territory. States have also trained, and continue to train, certain animals—principally marine mammals such as bottlenose dolphins and California sea lions—to perform military tasks, like ship and harbor protection, or mine detection and clearance. Millions of horses, mules, donkeys, camels, dogs, and birds are obliged to serve on various fronts (transport, logistics, or communications) and become particularly vulnerable targets.

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Hydrodynamic drag in steller sea lions (Eumetopias jubatus)

Journal of Experimental Biology ◽

10.1242/jeb.203.12.1915 ◽

2000 ◽

Vol 203 (12) ◽

pp. 1915-1923 ◽

Cited By ~ 6

Author(s):

L.L. Stelle ◽

R.W. Blake ◽

A.W. Trites

Keyword(s):

Minimum Cost ◽

The Body ◽

Hydrodynamic Drag ◽

Eumetopias Jubatus ◽

Steller Sea Lions ◽

California Sea Lions ◽

Cost Of Transport ◽

Sea Lions ◽

Drag Forces ◽

The Individual

Drag forces acting on Steller sea lions (Eumetopias jubatus) were investigated from ‘deceleration during glide’ measurements. A total of 66 glides from six juvenile sea lions yielded a mean drag coefficient (referenced to total wetted surface area) of 0.0056 at a mean Reynolds number of 5.5×10(6). The drag values indicate that the boundary layer is largely turbulent for Steller sea lions swimming at these Reynolds numbers, which are past the point of expected transition from laminar to turbulent flow. The position of maximum thickness (at 34 % of the body length measured from the tip of the nose) was more anterior than for a ‘laminar’ profile, supporting the idea that there is little laminar flow. The Steller sea lions in our study were characterized by a mean fineness ratio of 5.55. Their streamlined shape helps to delay flow separation, reducing total drag. In addition, turbulent boundary layers are more stable than laminar ones. Thus, separation should occur further back on the animal. Steller sea lions are the largest of the otariids and swam faster than the smaller California sea lions (Zalophus californianus). The mean glide velocity of the individual Steller sea lions ranged from 2.9 to 3.4 m s(−)(1) or 1.2-1.5 body lengths s(−)(1). These length-specific speeds are close to the optimum swim velocity of 1.4 body lengths s(−)(1) based on the minimum cost of transport for California sea lions.

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Colony Location and Captivity Influence the Gut Microbial Community Composition of the Australian Sea Lion (Neophoca cinerea)

Applied and Environmental Microbiology ◽

10.1128/aem.00192-16 ◽

2016 ◽

Vol 82 (12) ◽

pp. 3440-3449 ◽

Cited By ~ 33

Author(s):

Tiffany C. Delport ◽

Michelle L. Power ◽

Robert G. Harcourt ◽

Koa N. Webster ◽

Sasha G. Tetu

Keyword(s):

Microbial Community ◽

Marine Mammals ◽

Animal Health ◽

Sea Lion ◽

Content Type ◽

Sea Lions ◽

Neophoca Cinerea ◽

Australian Sea Lion ◽

Captive Populations ◽

Gut Microbial Community

ABSTRACTGut microbiota play an important role in maintenance of mammalian metabolism and immune system regulation, and disturbances to this community can have adverse impacts on animal health. To better understand the composition of gut microbiota in marine mammals, fecal bacterial communities of the Australian sea lion (Neophoca cinerea), an endangered pinniped with localized distribution, were examined. A comparison of samples from individuals across 11 wild colonies in South and Western Australia and three Australian captive populations showed five dominant bacterial phyla:Firmicutes,Proteobacteria,Bacteroidetes,Actinobacteria, andFusobacteria. The phylumFirmicuteswas dominant in both wild (76.4% ± 4.73%) and captive animals (61.4% ± 10.8%), whileProteobacteriacontributed more to captive (29.3% ± 11.5%) than to wild (10.6% ± 3.43%) fecal communities. Qualitative differences were observed between fecal communities from wild and captive animals based on principal-coordinate analysis. SIMPER (similarity percentage procedure) analyses indicated that operational taxonomic units (OTU) from the bacterial familiesClostridiaceaeandRuminococcaceaewere more abundant in wild than in captive animals and contributed most to the average dissimilarity between groups (SIMPER contributions of 19.1% and 10.9%, respectively). Differences in the biological environment, the foraging site fidelity, and anthropogenic impacts may provide various opportunities for unique microbial establishment in Australian sea lions. As anthropogenic disturbances to marine mammals are likely to increase, understanding the potential for such disturbances to impact microbial community compositions and subsequently affect animal health will be beneficial for management of these vulnerable species.IMPORTANCEThe Australian sea lion is an endangered species for which there is currently little information regarding disease and microbial ecology. In this work, we present an in-depth study of the fecal microbiota of a large number of Australian sea lions from geographically diverse wild and captive populations. Colony location and captivity were found to influence the gut microbial community compositions of these animals. Our findings significantly extend the baseline knowledge of marine mammal gut microbiome composition and variability.

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Development, Comparison, and Validation Using ELISAs for the Determination of Domoic Acid in California Sea Lion Body Fluids

Journal of AOAC International ◽

10.5740/jaoacint.sgeseubert ◽

2014 ◽

Vol 97 (2) ◽

pp. 345-355 ◽

Cited By ~ 10

Author(s):

Erica L Seubert ◽

Meredith D A Howard ◽

Raphael M Kudela ◽

Thomas N Stewart ◽

R Wayne Litaker ◽

...

Keyword(s):

Domoic Acid ◽

Matrix Effects ◽

Body Fluids ◽

Sea Lion ◽

California Sea Lions ◽

California Sea Lion ◽

Sea Lions ◽

Technical Capability ◽

Analytical Platforms

Abstract Mortalities of California sea lions (Zalophus californianus) attributed to the neurotoxin domoic acid (DA) produced by the diatom Pseudo-nitzschia have occurred repeatedly along the U.S. west coast since the late 1990s. Quantifying the amount of DA in these animals and correlating this information with the presence of DA in phytoplankton and the local food web has become a research focus for many scientists. However, differences in materials, equipment, technical capability, budgets, and objectives of the various groups and/or agencies involved in this work have influenced the DAquantification platforms used. The goal of the present study was to compare the performance of two commercially available ELISAs for the determination of DAin a spectrum of California sea lion body fluids andto compare the results with LC/MS of the same samples. The results indicated differences among these approaches, presumably owing to matrix effects (particularly urine) and antibody reactivities. This information implies that care should be taken in attemptingto compare datasets generated using different analytical platforms and interpreting the results of published studies.

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Evidence of a ‘dinner bell’ effect from acoustic transmitters in adult Chinook salmon

Marine Ecology Progress Series ◽

10.3354/meps13323 ◽

2020 ◽

Vol 641 ◽

pp. 1-11

Author(s):

AM Wargo Rub ◽

BP Sandford

Keyword(s):

Chinook Salmon ◽

Marine Mammals ◽

Oncorhynchus Tshawytscha ◽

Spatial Scales ◽

California Sea Lions ◽

Sea Lions ◽

Acoustic Transmitter ◽

Archival Tags ◽

Significant Difference ◽

Survival Differences

The ‘dinner bell’ hypothesis posits that marine mammals hear or otherwise sense soundwaves produced by acoustic transmitters and use the signal to selectively prey on fish carrying them. A dual tagging study conducted during 2010 and 2011 supports this hypothesis. Results from this study revealed a significant difference in the survival of fish marked with passive integrated transponder (PIT) tags and those marked with active acoustic transmitters. Our objective had been to use both types of tags to study behavior and survival of migrating adult spring Chinook salmon Oncorhynchus tshawytscha at 2 different spatial scales. We tagged fish as they entered the Columbia River, USA, and monitored their survival and progress over a 193 km reach to Bonneville Dam (river km 234), its lowest impoundment. In 2010, estimated survival was 0.74 (95% CI, 0.62-0.86) for PIT-tagged fish but only 0.30 (0.15-0.45) for acoustic-tagged fish. Therefore, in 2011, we included archival tags and a sham acoustic transmitter group to help identify causes of the survival discrepancy. Survival was 0.75 (0.54-0.97) for sham transmitter fish and 0.73 (0.60-0.86) for PIT fish, but only 0.10 (0.00-0.24) for active acoustic transmitter fish. Our study area was replete with harbor seals Phoca vitulina, California sea lions Zalophus californianus, and Steller sea lions Eumetopias jubatus during both years. We suspect the most likely cause of survival differences between tag treatment groups was pinniped predation. Using temperature data from archival tags, we found evidence of such predation and support for a ‘dinner bell’ effect from acoustic transmitter tags.

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Homing by released captive California sea lions, Zalophus californianus, following release on distant islands

Canadian Journal of Zoology ◽

10.1139/z85-317 ◽

1985 ◽

Vol 63 (9) ◽

pp. 2162-2164 ◽

Cited By ~ 7

Author(s):

S. H. Ridgway ◽

C. C. Robison

Keyword(s):

San Diego ◽

Zalophus Californianus ◽

Sea Lion ◽

California Sea Lions ◽

San Nicolas Island ◽

Sea Lions ◽

San Diego Bay ◽

East West ◽

San Clemente Island

Captive male California sea lions were twice flown to offshore breeding islands and released. Three animals returned to their pen in San Diego Bay after discharge on San Clemente Island, about 115 km away. Two of four returned to the same facility from San Nicolas Island, about 240 km away. The fastest sea lion returned in 2 days from San Clemente and in 4 days from San Nicolas. This is the first evidence for such specific east–west navigation by sea lions and suggests that these animals are good navigators.

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